chocolate & chestnut yule log

candied chestnut & chocolate half-spheres :

• combine the 3 different broken chocolate pieces in 6 small tins to create 6 colors of chocolate (very dark brown, dark brown, medium-dark brown, milk chocolate, beige, white chocolate) and place in a pan of hot (almost simmering) water, carefully stirring until melted (remove from heat to avoid burning)
• create 12 disks or half-domes using a silicone mold by spooning the warm chocolate mixture into each cavity, place the small candied chestnut (or chocolate-coated almonds or hazelnuts) in the middle of each and set aside in the refrigerator until cooled and hardened, un-mold and set aside in a container in the refrigerator

sheet sponge cake :

• preheat the oven to 180°C
• use a roulade tray (rectangular flat baking dish for making cakes that will be rolled) and line with baking paper (I use a 25 cm x 35 cm x 3 cm silicone baking tray which does not require lining because it is flexible, so I simply brush it with melted butter and sprinkle it with flour)
• melt the dark chocolate in a double-boiler (bain-marie) until smooth and set aside to cool slightly
• whisk the egg whites with a pinch of salt and several drops of lemon juice until stiff and set aside
• in another bowl, whisk the egg yolks, sugar and vanilla extract until paler, thick and creamy
• whisk the melted, cooled chocolate, chestnut flour, instant coffee powder and salt into the egg yolks and sugar mixture, then add several tablespoons of the whipped egg whites and keep whipping to loosen up the batter mixture
• gently fold in the remaining egg whites with a large wooden spoon or rubber spatula, being careful not to lose most of the air bubbles
• pour the batter into your prepared tin (or silicon baking dish), smooth it out and bake for 18-20 minutes maximum (or until an inserted skewer comes out clean / be careful not to dry it out !)
• transfer the slightly warm flat sheet cake onto a sheet of baking paper heavily sprinkled with cocoa powder, sprinkle more cocoa powder on top and then gently roll into a cylinder to initially form it, then unroll and set aside to cool almost completely for 30 minutes (don’t worry about cracks and splits)

chestnut cream filling :

• whip the mascarpone cream with the sweetened chestnut purée
• spread a thick layer of the chestnut cream onto the flat sponge cake and sprinkle with the finely chopped candied chestnuts
• roll up the cake (using the baking paper to help you) and transfer to a large kitchen towel lined with a smaller piece of baking paper (with the seam on the underside) placed on a cutting board and chill in the refrigerator for 1-2 hours or until ready to apply the chocolate cream ganache frosting

chocolate cream ganache frosting :

• before beginning, remove the cake log from the refrigerator, slice off the ends (about 1 cm) to even it out and make it neater and place on a rack before making the frosting
• break up the dark 70% chocolate into smaller pieces and melt in a double-boiler (bain-marie) while warming the sweetened condensed milk and vanilla extract in another smaller casserole
• combine both warm mixtures together and whisk until smooth and pour the warm chocolate cream ganache on top of the cake, placed over a rack to recuperate the extra chocolate and spread evenly over the cake and all sides (covering and filling up any cracks and splits)
• note : temperature differences and chocolate quality can alter the ganache, making it too thick at times, have some extra warmed sweetened condensed milk at hand to add extra if necessary to make it less thick …

decorations and garnish :

• before the frosting hardens, immediately sprinkle the yule log with rock sugar, cocoa nibs and some flakes of sea salt and decorate with the 12 disks of candied chestnut & chocolate drops
• note : you can use other decorations such as chocolate covered almonds and hazelnuts (or even different types of fancy Belgian or French chocolates from a gift-box of chocolates) ...
• loosely cover the decorated yule log with aluminum foil (or create a tent with the foil) and keep chilled in the refrigerator until ready to serve in thick slices.